Viscous synergy and antagonism,excess molar volume,isoentropic compressibility and excess molar refraction of ternary mixtures containing tetrahydrofuran,methanol and six membered cyclic compounds at 298.15 K

The densities (ρ), viscosities (η), sound speeds (u) and refractive indices (n _D) of seven ternary mixtures of cyclic ether (tetrahydrofuran), methanoland cyclic compounds; benzene, toluene, chlorobenzene, nitrobenzene, anisole, cyclohexane and cyclohexanone are determined over the entire range of composition at 298.15?K. From the experimental observations, viscosity deviation (Δη), the viscous synergy and antagonism, synergic and antagonic index are derived by the equations developed by Kalentunc-Gencer and Peleg [G. Kalentunc-Gencer and M. Peleg, J. Texture Stud. 17, 61 (1986)] and Howell [N.K. Howell, Presented at the Proceedings of the Seventh International Conference, Wales, 1993], respectively. Excess molar volume (V ^E), excess isoentropic compressibility (ΔK _S) and excess molar refraction (ΔR) have been calculated from the experimentally measured density, sound speed and refractive index values. The excess Gibb's free energy of activation (ΔG ^E) has also been calculated. The results are discussed and interpreted in terms of molecular package and specific interaction predominated by hydrogen bonding.     

Studies on solution properties of ternary mixture of acetophenone + n-amyl alcohol + dichloromethane and its corresponding binaries at 298.15 K

The excess values of molar volume (V ^E), viscosity deviation (Δη), deviation in isentropic compressibility (ΔK_S ), excess molar refraction (ΔR) and excess Gibbs energy of activation (ΔG^*E ) of viscous flow have been investigated from the experimentally measured densities, viscosities, sound speeds and refractive indices for three binary mixtures of acetophenone?+?n-amyl alcohol, acetophenone?+?dichloromethane and n-amyl alcohol?+?dichloromethane and their corresponding ternary mixtures at 298.15?K over the entire composition range. The calculated quantities are further fitted to the Redlich–Kister equation to estimate the binary fitting parameters and standard deviations from the regression lines. The excess or deviation properties were found to be either negative or positive depending on the molecular interactions and the nature of liquid mixtures and have been discussed in terms of molecular interactions and structural changes.     

Comments concerning ‘study of molecular interaction in binary liquid mixtures of ethyl acetoacetate with chloroform and dimethylsulphoxide using excess acoustic parameters and spectroscopic methods’

The measured excess molar volume data in the recently published paper for the binary chloroform + ethyl acetoacetate system are shown to differ significantly from previously published data. Excess adiabatic compressibilities reported in the paper are shown to be calculated from an incorrect thermodynamic expression.     

Physicochemical investigation on interactions of some amino acids with aqueous tetra-butyl ammonium bromide solution at 298.15 K

Apparent molar volumes, viscosity B-coefficients, and apparent molar isentropic compressibilities of glycine, L-alanine, L-valine and L-leucine in 0.062, 0.125 and 0.256 mol kg^?1 aqueous tetra-butyl ammonium bromide (TBAB) solution have been determined at 298.15 K from their experimental density, flow time and sound speed measurements, respectively. The standard partial molar volumes and compressibilities are used to calculate the corresponding volume of transfer at infinite dilution, from water to aqueous TBAB solutions. The linear correlation of partial molar volumes for a homologous series of amino acids has been utilised to calculate the contribution of charged end groups and other alkyl chains of the amino acids to partial molar volumes. The hydration numbers of amino acids have also been determined. Viscosity B-coefficients have been calculated using the Jones–Dole equation. The values of the charged end groups contribution to the viscosity B-coefficients of the amino acids are calculated.     

Molar and partial molar excess volumes of di-n-butylamine with chloroalkanes at 25°C

Molar excess volumes and partial molar excess volumes are reported for binary mixtures of dibutylamine+dichloromethane, trichloromethane and tetrachloromethane at 25°C, over the whole concentration range. A comparative study is made between the primary and secondary amines and their mixtures with chloroalkanes. The applicability of the so-called ERAS model for predicting thermodynamic excess properties is tested here for excess molar volumes; the calculated values agree quite well with experimental data.     

Volumetric,viscometric and acoustic properties of binary mixtures of 2-propanol with n -alkanes (C6, C8, C10) at 298.15 and 308.15 K

Densities (ρ), viscosities (η), and speeds of sound, (u) of the binary mixtures of 2-propanol with n-alkanes (n-hexane, n-octane, and n-decane) were measured over the entire composition range at 298.15 and 308.15 K and at atmospheric pressure. Using the experimental values of density, viscosity and speed of sound, the excess molar volumes (V ^E), viscosity deviations (Δη), deviations in speed of sound (Δu), isentropic compressibility (κ _s), deviations in isentropic compressibility (Δκ _s), and excess Gibbs energies of activation of viscous flow (ΔG* ^E) were calculated. These results were fitted to the Redlich–Kister type polynomial equation. The variations of these excess parameters with composition were discussed from the viewpoint of intermolecular interactions in these mixtures. The excess properties are found to be either positive or negative depending on the molecular interactions and the nature of liquid mixtures.     

Excess molar volumes and excess viscosities for then-hexane+dichloromethane+tetrahydrofuran ternary system at 25°C

Exces molar volumes, and excess viscosities of then-hexane+dichloromethane+tetrahydrofuran system have been determined at 25°C by measuring densities and viscosities. Different expressions exist in the literature to predict these excess properties from binary data. The empirical correlation of Cibulka is shown to be the best in this system.     

Molar excess heat capacities and volumes for mixtures of alkanoates with cyclohexane at 25°C

Molar excess volumes V ^E at 25°C have been determined by vibrating-tube densimetry, as a function of mole fraction x for different series of an alkanoate (H _2m+1 C _m COOC _n H _2n+1 )+cyclohexane. Three types of alkanoates were investigated, i.e., methanoates (m=0, with n=3 and 4), ethanoates (m=1, with n=2, 3, and 4) and propanoates (m=2, with n=1, 2, and 3). In addition, a Picker flow calorimeter was used to obtain molar excess heat capacities C _p ^E at constant pressure at the same temperature. V ^E is positive for all systems and rather symmetric, with V ^E (x=0.5) amounting to almost identical values in a series of mixtures containing an alkanoate isomer of same formula (say C₄H₈O₂, C₅H₁₀O₂, or C₆H₁₂O₂). The composition dependence of C _p ^E is rather unusual in that two more or less marked minima are observed for most of the mixtures, especially when the alkanoate is a methanoate or an ethanoate. These results are discussed in terms of possible changes in conformation of both the ester and cyclohexane.     

Binary mixtures of cyclohexanone, 2-butanone, 1,4-dioxane and 1,2-dimethoxyethane

Densities and sound velocities of binary mixtures of cyclohexanone, 2-butanone, 1,4-dioxane and 1,2-dimethoxyethane were measured at 298.15 K and also the densities at 303.15 K. Excess volumes were determined from densities. Isentropic compressibilities were determined from densities and sound velocities, and excess thermal expansion factors were determined from excess volumes of two temperatures. Excess isothermal compressibilities and excess isochoric heat capacities were then estimated using excess isobaric heat capacities previously reported. Excess volumes and excess isentropic and isothermal compressibilities were negative except for cyclohexanone+1,4-dioxane system. This revised version was published online in August 2006 with corrections to the Cover Date.     

Physico-chemical properties of binary mixtures of 1-butanol with chloroethanes or chloroethenes at 298.15 K

The densities ρ, speeds of sound u, and viscosities η, of pure 1-butanol, 1,2-dichloroethane, 1,1,1-trichloroethane, 1,1,2,2-tetrachloroethane, trichloroethylene, and tetrachloroethylene and those of their binary mixtures have been measured at 298.15 K and atmospheric pressure over the entire range of compositions. Excess molar volumes V ^E, viscosity deviations Δη, deviation in compressibilities Δκ_s and excess Gibbs energy of activation G*^E, were obtained from the experimental results and those were fitted to Redlich–Kister's type function in terms of mole fractions. Viscosities, speeds of sound and isentropic compressibilities of the binary mixtures have been correlated by means of several empirical and semi-empirical equations. The experimental data are analysed to discuss the nature and strength of intermolecular interactions in these mixtures.     

Molecular interaction study through experimental and theoretical volumetric,transport and refractive properties of N-ethylaniline with aryl and alkyl ethers at several temperatures

To investigate the molecular interaction study between secondary amine with aryl and alkyl ether, we report densities, speeds of sound, viscosities and refractive indices of N-ethylaniline (NEA) with aryl (anisole, phenetole) and alkyl (tert-butyl methyl ether) ether over the entire composition regime and in the temperature range of 293.15–323.15 K at 5 K intervals. Various excess and transport properties were derived from the experimental data and the excess parameters were fitted to the Redlich–Kister polynomial equation using multiparametric non-linear regression analysis to derive the binary coefficients and to estimate the standard deviation. Molecular interactions between the unlike molecules were analysed through dipole–dipole interactions, cross-association between the components of the mixtures and H-bond formation. Viscosity and refractive index of the mixtures were predicted through several empirical equations and compared with the experimental results. Prigogine–Flory–Patterson statistical theory was used to predict the excess molar volume results.     

Acoustical and excess thermodynamic studies of mixtures of 2-pyrrolidone with 1,3-propanediol and water as well as 1,3-propanediol with water at 308.15 K

The density (ρ), viscosity (η) and ultrasonic velocity (u) of three mixtures consisting of 2- pyrrolidone with 1,3-propanediol (PD) and water and also of PD and water have been measured as a function of mole fraction at 308.15 K. The experimentally collected data has been used to calculate the excess molar volume (V^E), deviation in viscosity (Δη), deviation in ultrasonic velocity (Δu), isentropic compressibility (κ_s), deviation in isentropic compressibility (Δκ_s) and excess Gibbs free energy of activation (ΔG*^E). The Redlich–Kister polynomial equation has been used to fit the derived parameters. The variation in excessive thermodynamic properties as a consequence of possible molecular interactions is discussed.     

Excess and partial excess molar volumes of 1,4-dichlorobutane with butanols at 25 and 40°C

From density measurements over the whole composition range at 25 and 40°C excess molar volumes for binary mixtures of 1,4-dichlorobutane with l-butanol, 2-butanol, 2-methyl-l-propanol or 2-methyl-2-propanol are calculated. V^E results were fitted by the method of least squares to a smoothing equation. Excess partial molar volumes and limiting excess partial molar volumes at 25° are also calculated.     

Excess volumes and excess viscosities of binary mixtures of cyclic ethers with bromobenzene

From density and viscosity measurements at 25 and 40°C, excess volumes and excess viscosities of the binary mixtures of a cyclic ether with bromobenzene were determined. The results are correlated by means of a Redlich-Kister type equation and interpreted in terms of molecular interactions.     

Experimental and predicted excess molar volumes of the ternary system.

Summary Experimental excess molar volumes for the ternary system x₁MTBE+x₂1-propanol+(1-x₁-x₂) heptane and the three involved binary mixtures have been determined at 298.15 K and atmospheric pressure. Excess molar volumes were determined from the densities of the pure liquids and mixtures, using a DMA 4500 Anton Paar densimeter. The ternary mixture shows maximum values around the binary mixture MTBE+heptane and minimum values for the mixture MTBE+propanol. The ternary contribution to the excess molar volume is negative, with the exception of a range located around the rich compositions of 1-propanol. Several empirical equations predicting ternary mixture properties from experimental binary mixtures have been applied.     

Effect of tetrahydrofuran on the conductance and ion-pairing of hydrogen chloride in wet and dry methanol mixtures

The molar conductance of dilute solutions of HCl in wet (68.5% methanol + 31.5% tetrahydrofurane mixtures at 25°C have been measured. The data were analyzed using the Fuoss-Hsia equation to calculate the infinite dilution molar conductances and association constants. The trend of the limiting conductances in these mixtures as a function of the water content shows, once more, the peculiar minimum due to the anomalous proton conductance mechanism. From these data the limiting molar conductance in the anhydrous binary solvent system was evaluated. The percentage excess proton mobility with respect to potassium ion has also been determined. All these data are compared to those found in a binary isodielectric methanol mixture containing as cosolvent 1,4-dioxane. This comparison shows that proton mobilities are very similar in both solvent mixtures. The dielectric constants, refractive indices, viscosities and densities of the methanol-tetrahydrofuran mixtures in the whole mole fraction range have been measured and are reported. An analysis of the excess molar volumes and viscosities shows a slight deviation of this system from ideality.     

Densities and viscosities of propylene carbonate with aromatic hydrocarbons (benzene, 1,4-dimethylbenzene and ethylbenzene) at 288.15, 298.15 and 308.15 K

Densities and viscosities of the binary mixtures of propylene carbonate with benzene, 1,4-dimethylbenzene and ethylbenzene were measured over the entire mole fraction range at 288.15, 298.15 and 308.15?K. Using the experimental values of densities and viscosities the excess molar volumes and viscosity deviations were calculated. The results were fitted by Redlich–Kister equation. The results were discussed in terms of intermolecular interactions.